XV144 - does it power spike
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Having just been told the reason I've blown the finals in 2 (possibly 3) 2m apps is because the FT-857 gives a spike of 50w when you PTT (regardless of what the Tx power is set to on the FT-857) before it settles down to the power set in the menu...
Can anyone tell me if the XV144 does this - I have one I've been meaning to build for some time and I guess this is the final straw that will get me to do so. 73 de David, M0XDF (K3 #174, P3 #108) -- Never let your sense of morals get in the way of doing what's right. -Isaac Asimov, scientist and writer (1920-1992) ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In a recent message, "David Ferrington, M0XDF" <[hidden email]>
writes >Can anyone tell me if the XV144 does this - I have one I've been >meaning to build for some time and I guess this is the final straw that >will get me to do so. No such problems here. Build it, David, you've been talking about it long enough ;-) 73 de David G4DMP -- + - - - - - - - - - - - - - - - - + | David M Pratt, Kippax, Leeds. | | Website: http://www.g4dmp.co.uk | + - - - - - - - - - - - - - - - - + ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: XV144 - does it power spike
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In reply to this post by M0XDF
David,
The XV144 does not do that on its own. If you are driving it with a K2 or K3, I know you will be OK, But if you are driving the XV144 with something else, be certain that it does not produce a poweer spike in the 28 MHz output. 73, Don W3FPR On 12/20/2012 1:07 PM, David Ferrington, M0XDF wrote: > Having just been told the reason I've blown the finals in 2 (possibly 3) 2m apps is because the FT-857 gives a spike of 50w when you PTT (regardless of what the Tx power is set to on the FT-857) before it settles down to the power set in the menu... > > Can anyone tell me if the XV144 does this - I have one I've been meaning to build for some time and I guess this is the final straw that will get me to do so. > > 73 de David, M0XDF (K3 #174, P3 #108) ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by David Pratt
Yes, your right David :-( Life just seems to get in the way
73 de David, M0XDF (K3 #174, P3 #108) -- Don‘t complain. Nobody will understand. Or care. And certainly don‘t try to fix the situation yourself. It‘s dangerous. Leave it to a highly untrained, unqualified, expendable professional. On 20 Dec 2012, at 18:15, David G4DMP wrote: > In a recent message, "David Ferrington, M0XDF" <[hidden email]> > writes >> Can anyone tell me if the XV144 does this - I have one I've been >> meaning to build for some time and I guess this is the final straw that >> will get me to do so. > > No such problems here. Build it, David, you've been talking about it > long enough ;-) > > 73 de David G4DMP > > -- > + - - - - - - - - - - - - - - - - + > | David M Pratt, Kippax, Leeds. | > | Website: http://www.g4dmp.co.uk | > + - - - - - - - - - - - - - - - - + > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Don Wilhelm-4
Thanks Don, a clear concise, authoritative post as always. Will be driven by my K3.
73 de David, M0XDF (K3 #174, P3 #108) -- It is almost impossible to carry the torch of truth through a crowd without singeing somebody's beard. -George Christopher Lichtenberg, scientist and philosopher (1742-1799) On 20 Dec 2012, at 18:55, Don Wilhelm wrote: > David, > > The XV144 does not do that on its own. > If you are driving it with a K2 or K3, I know you will be OK, > But if you are driving the XV144 with something else, be certain that it does not produce a poweer spike in the 28 MHz output. > > 73, > Don W3FPR > > > On 12/20/2012 1:07 PM, David Ferrington, M0XDF wrote: >> Having just been told the reason I've blown the finals in 2 (possibly 3) 2m apps is because the FT-857 gives a spike of 50w when you PTT (regardless of what the Tx power is set to on the FT-857) before it settles down to the power set in the menu... >> >> Can anyone tell me if the XV144 does this - I have one I've been meaning to build for some time and I guess this is the final straw that will get me to do so. >> >> 73 de David, M0XDF (K3 #174, P3 #108) > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by David Pratt
Hello David,
I have the internal transverter that is similar to the kit that you have and I do not experience any spike at commencement of transmission. 73 Peter G3SMT ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by M0XDF
Most of the YaKeIc I've ever worked with have this issue. Anytime you use ALC to control the power output there is a chance that that can happen if you are turning the power way down. When the rig is first keyed, there is a window before the ALC voltage is set properly that can allow this. It may be only milliseconds but with solid state devices, that could be all it takes. With transveters in general, they operate from a low level stage and the effects on ALC are either minimal or non-existant. In the case of the K2 and K3's with their external transverters, I do not believe they incorporate any ALC so whatever you set the drive level to, that's all you get. For many years we at K8GP used TS850's to drive DEM transverters using the low level outputs from the 850's and never had an issue. Now that we have many K3's in the group (YEA!!!!), they even work better. Now the nay-sayers will condem not using ALC but in the transverter world, the correct way to set one up is to watch
the output power while increasing the drive level. Once a peak is reached (or you get to the amount of drive needed for your amp), back the drive off slightly and you are done, you can't overdrive it that way. So while some folks shy away from transverters because they might think they are too complicated, the performance you get from an Elecraft transverter and a K3 FAR outperforms ANY multimode-multiband rig regardless of manufacturer. 73, Merry Xmas to all. Terry Price - W8ZN ex K8ISK FM18dv - 1.8MHz thru 47GHz K8GP - The Grid Pirates - FM19bb ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: XV144 - does it power spike
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In reply to this post by M0XDF
W8ZN shared:
> Most of the YaKeIc I've ever worked with have this issue. Anytime you > use ALC to control the power output there is a chance that that can > happen if you are turning the power way down. When the rig is first > keyed, there is a window before the ALC voltage is set properly that > can allow this. It may be only milliseconds but with solid state > devices, that could be all it takes. I think this might be product specific, as ! never experienced this with any Brand-I or Brand-K & only with one Brand-Y product I have had or used over the years. On that particular Brand-Y product, there is overshoot only when reducing power from the front panel control - not when the rear panel spigot is pulled negative - the exact opposite of what is mentioned above. Probably best to check, as Terry says that little overshoot can damage - or if one of those rigs were driving something like a KPA500, spit out a bit of splatter that isn't nice. 73, ex-VR2BG/p. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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